Heat sinks with vibration enhanced heat transfer

ABSTRACT

The heat sinks with vibration enhanced heat transfer are heat sinks formed from a first body of high thermal conductivity material. The first body of high thermal conductivity material is received within a thermally conductive housing such that at least one contact face of the first body of high thermal conductivity material is exposed, forming a direct contact interface with a heat source requiring cooling. The heat source requiring cooling may be a liquid heat source, including but not limited to water. The thermally conductive housing is disposed such that at least one contact face of the thermally conductive housing is in direct contact with the vibrating base. The vibrating base applies oscillating waves to the heat sink, thereby increasing heat transfer between the heat source and the heat sink.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of Ser. No. 16/664,504, filed Oct.25, 2019, which application claims the benefit of U.S. ProvisionalPatent Application Ser. No. 62/750,796, filed Oct. 25, 2018.

BACKGROUND 1. Field

The disclosure of the present patent application relates to heat sinks,and particularly to a heat sink with vibration enhanced heat transfer.

2. Description of the Related Art

As electronic technology continues to advance, electronic components,such as processor chips, are being made to provide faster operationalspeeds and greater functional capabilities. When a typical processorchip or a similar integrated circuit or modular circuit package operatesat a high speed inside a computer or device housing, its temperatureincreases at a rapid rate. It is therefore necessary to dissipate thegenerated heat before any damage to the system may occur.

Conventionally, a heat sink is used to dissipate heat generated by aprocessor or the like. A conventional heat sink includes a base, whichmakes direct contact with the heat source, and a plurality of coolingfins. The heat sink dissipates heat by conduction through the base andinto the fins, followed by convective cooling of the fins. However, asthe power of electronic devices increases, so does the heat generated bytheir internal components, thus requiring heat sinks that are capable ofdissipating heat far more effectively. For this reason, liquid coolingsystems were developed to provide more efficient heat removal.

Vibration has also been used to enhance certain characteristics ofconventional heat sinks and heat spreaders. For example, an LED moduleincluding a heat sink with a vibrating fin has been taught to improvecooling performance. Conventionally, a heat spreader is generally usedto rapidly disperse heat across an area, and may be used in combinationwith a heat sink. A heat spreader including a liquid filled internalspace between two thin films and a vibration means for vibrating theliquid have been taught to improve heat spread performance.

Although such phase change material-type heat sinks and/or vibrationenhanced heat sinks/spreaders are more efficient than conventional heatsinks/spreaders, these heat sinks/spreaders are still limited in theireffectiveness. A typical water-based phase change material-type heatsink, as described above, is limited in its effectiveness primarily dueto design considerations, such as thermal conductivity and heat capacityof the materials involved as functions of the physical dimensions of theheat sink. The heat sinks/spreaders incorporating vibration are alsolimited by design considerations, specifically in that the vibration isapplied to cooling fins or to increase the rate at which the heat isdispersed in a liquid reservoir. Thus, heat sinks with vibrationenhanced heat transfer solving the aforementioned problems are desired.

SUMMARY

In one embodiment, the present subject matter is directed to a heat sinkwith a vibrating base. In this embodiment, the heat sink is formed froma first body of high thermal conductivity material. The first body ofhigh thermal conductivity material is received within a thermallyconductive housing such that at least one contact face of the first bodyof high thermal conductivity material is exposed, forming a directcontact interface with a heat source requiring cooling. The heat sourcerequiring cooling may be any liquid heat source, including but notlimited to a hot immiscible liquid. The thermally conductive housing hasat least one wall and is disposed such that at least one contact face ofthe thermally conductive housing is in direct contact with the vibratingbase.

In use, heat generated by the heat source is transferred, viaconduction, into the first body of high thermal conductivity material.The heat from the heat source may cause at least a portion of the firstbody of high thermal conductivity material, if solid, to at leastpartially liquefy, forming a conductive melted high thermal conductivitymaterial layer within the first body of high thermal conductivitymaterial and disposed in direct contact with the heat source. In thisembodiment, the material chosen to form the first body of high thermalconductivity material is selected such that the conductive melted highthermal conductivity material layer is immiscible with the hotimmiscible liquid heat source.

In another embodiment, the first body of high thermal conductivitymaterial may be a liquid material disposed in direct contact with theheat source. In this embodiment, the liquid material chosen as the firstbody of high thermal conductivity material is immiscible with the hotimmiscible liquid heat source. Other liquid materials that would mixwith the hot immiscible liquid heat source cannot be used as the firstbody of high thermal conductivity material.

The first body of high thermal conductivity material will thus absorband store latent and sensible heat until it can be transferred byconvection through the thermally conductive housing and be dissipatedinto the surrounding environment. The vibrating base may applyoscillating waves, propagating through the thermally conductive housingand/or the first body of high thermal conductivity material, to reachthe direct contact interface and thereby increasing heat transferbetween the heat source and the first body of high thermal conductivitymaterial, and/or between the heat source and the conductive melted highthermal conductivity material layer, and/or between the conductivemelted high thermal conductivity material layer and the rest of thefirst body of high thermal conductivity material. At the direct contactinterface, the vibration may generate active dynamic motions of themolecules of the first body of high thermal conductivity material, theconductive melted high thermal conductivity material layer, or the heatsource thereby dilating the direct contact interface, increasing thesurface area of contact between the heat source and the first body ofhigh thermal conductivity material or the conductive melted high thermalconductivity material layer, and further increasing the rate of heattransfer from the heat source to the heat sink.

In an embodiment, the heat source requiring cooling may be a hotimmiscible liquid.

These and other features of the present disclosure will become readilyapparent upon further review of the following specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source.

FIG. 1B is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source and having a conductive melted highthermal conductivity material layer.

FIG. 2A is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one tube.

FIG. 2B is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one tube and a conductivehigh thermal conductivity material layer.

FIG. 3A is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one internal chamber for asecond body of high thermal conductivity material and a conductivemelted high thermal conductivity material layer.

FIG. 3B is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one internal chamber for asecond body of high thermal conductivity material and a conductivemelted high thermal conductivity material layer.

FIG. 4A is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one thermally conductivevertical stud and a conductive melted high thermal conductivity materiallayer.

FIG. 4B is a side view in section of an alternative embodiment of a heatsink with vibration enhanced heat transfer adapted for cooling of a hotimmiscible liquid heat source having at least one thermally conductivevertical stud and a conductive melted high thermal conductivity materiallayer, wherein the at least one thermally conductive vertical stud hasat least one internal chamber containing a second body of high thermalconductivity material.

FIG. 5 is a graph representing the temperature of a heat source exposedto oscillating vibrations at 20 Hz with varying amplitudes.

FIG. 6 is a graph representing the temperature of a heat source exposedto oscillating vibrations at 35 Hz with varying amplitudes.

FIG. 7 is a graph representing the temperature of a heat source exposedto oscillating vibrations at 50 Hz with varying amplitudes.

Similar reference characters denote corresponding features consistentlythroughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The heat sink with vibrating base is formed from a first body of highthermal conductivity material. The first body of high thermalconductivity material is received within a thermally conductive housingsuch that at least one contact face of the first body of high thermalconductivity material is exposed, forming a direct contact interfacewith a heat source requiring cooling. The heat source requiring coolingmay be any liquid heat source, including but not limited to a hotimmiscible liquid. The thermally conductive housing has at least onewall and is disposed such that at least one contact face of thethermally conductive housing is in direct contact with the vibratingbase. The high thermal conductivity material may be a liquid material ora solid material. Thus, part or all of the first body of high thermalconductivity material may be liquefied prior to exposing the heat sinkto the heat source. The at least one wall of the thermally conductivehousing may have a plurality of fins mounted to at least a portionthereof, either outside or inside of the first body of solid highthermal conductivity material. The individual fins forming the pluralityof fins may have any orientation, may be straight or branched, may besolid or hollow, and/or may have any combination of these features.

As used herein, the term “approximately” when used to modify a numericalvalue means within 10% of said numerical value.

In use, heat generated by the heat source is transferred, viaconduction, into the first body of high thermal conductivity material.The heat from the heat source may cause at least a portion of the firstbody of high thermal conductivity material, if solid, to at leastpartially liquefy, forming a conductive melted high thermal conductivitymaterial layer within the first body of high thermal conductivitymaterial and disposed in direct contact with the heat source. Theconductive melted high thermal conductivity material layer may act as aliquid with a high thermal conductivity, thereby supporting heattransfer from the heat source to the conductive melted high thermalconductivity material layer and subsequently to the rest of the firstbody of high thermal conductivity material. Heat transfer via theconductive melted high thermal conductivity material layer may occur viaconduction and convection. The conductive melted high thermalconductivity material layer may transfer heat between the heat sourceand the first body of high thermal conductivity material and/or thethermally conductive housing by conduction or convection. The first bodyof high thermal conductivity material will thus absorb and store latentand sensible heat until it can be transferred by convection through thethermally conductive housing and be dissipated into the surroundingenvironment.

The vibrating base may be made of any suitable material; however, it ispreferably made of a material with a high thermal conductivity, such as,by way of non-limiting example, aluminum. The vibrating base may applyoscillating waves, propagating through the thermally conductive housingand/or the first body of high thermal conductivity material, to reachthe direct contact interface between the first body of high thermalconductivity material and the heat source requiring cooling, therebyincreasing heat transfer between the heat source and the first body ofhigh thermal conductivity material, and/or between the heat source andthe conductive melted high thermal conductivity material layer, and/orbetween the conductive melted high thermal conductivity material layerand the rest of the first body of high thermal conductivity material.The oscillating waves can be any kind of wave, including for examplesinusoidal waves or square waves. The oscillating waves may be appliedlaterally, vertically, or in any other direction. The oscillating wavesmay be generated by any known means, including but not limited tomechanical means, ultrasound, and electrical or magnetic effects.

At the direct contact interface, the oscillating waves (vibrations) maygenerate active dynamic motions of the molecules of the first body ofhigh thermal conductivity material and/or the conductive melted highthermal conductivity material layer, thereby increasing the rate of heattransfer from the heat source to the heat sink. The vibrations may alsodilate the direct contact interface, increasing the surface area ofcontact between the heat source and the first body of high thermalconductivity material or the conductive melted high thermal conductivitymaterial layer, further increasing the rate of heat transfer from theheat source to the heat sink.

The heat source may be any liquid that is immiscible in the liquid formof the first body of high thermal conductivity material, i.e., when aportion of the first body of a solid high thermal conductivity materialforms the conductive melted high thermal conductivity material layer orwhen the high thermal conductivity material is a liquid material. As anon-limiting example, the heat source may be water, an oil, ordielectric liquid, where the

has a density that is less than the density of the first body of highthermal conductivity material. The vibrations may be applied directly tothe heat sink and propagated through the first body of high thermalconductivity material.

In the embodiment of FIGS. 1A and 1B, the heat sink with vibrationenhanced heat transfer, designated generally as 10, is again a heat sinkformed from a first body of high thermal conductivity material 14disposed within a thermally conductive housing 12 such that at least onecontact face 30 of the first body of high thermal conductivity material14 is exposed, forming a direct contact interface 28 with at least oneface of at least one heat source HS that requires cooling. Similar toprevious embodiments, the thermally conductive housing 12 has at leastone wall 32 and at least one contact face 34, and said contact face 34of said thermally conductive housing 12 is adapted to be in directcontact with a vibrating base 20. In this embodiment the heat source HSis an immiscible liquid 18. It should be further understood that theoverall configuration and relative dimensions of the thermallyconductive housing 12, the first body of high thermal conductivitymaterial 14, and the vibrating base 20 are shown for purposes ofillustration only.

The thermally conductive housing 12 may be selected from any suitablematerial that is compatible with the selected first body of high thermalconductivity material 14. For example, aluminum would not be used as athermally conductive housing 12 material when the first body of highthermal conductivity material 14 includes elemental gallium. The atleast one wall 32 of the thermally conductive housing 12 may have aplurality of fins 22 mounted to at least a portion thereof, eitheroutside or inside of the first body of high thermal conductivitymaterial 14. It should be understood that the positioning, overallconfiguration, relative dimensions, and number of thermally conductivefins 22 are shown for exemplary purposes only.

The first body of high thermal conductivity material 14 may be formedfrom at least one high thermal conductivity material. The at least onehigh thermal conductivity material may be liquid at intended operatingconditions, or it may be a solid phase change material. The at least onehigh thermal conductivity material is selected such that it has a highthermal conductivity and, if the high thermal conductivity materialselected is a solid phase change material, is selected such that it hasa melting point between the temperature of the external environmentwithin which the heat sink 10 is intended to operate and the maximumoperating temperature of the heat source HS. As a non-limiting example,if a heat sink 10 is intended to operate in a room maintained at 20° C.and to cool a heat source with a maximum operating temperature of 60°C., elemental gallium having a melting point of approximately 30° C.might be selected for the first body of high thermal conductivitymaterial 14. If the at least one high thermal conductivity material is aliquid under the intended operating conditions and the heat source is aliquid, the selected material may have a higher density than the densityof the heat source material. In the embodiment of FIGS. 1A and 1B, theat least one high thermal conductivity material forming the first bodyof high thermal conductivity material 14 is also selected such that theimmiscible liquid 18 will be immiscible with any liquid or meltedportion of the first body of high thermal conductivity material 14 thatmay form during use of the heat sink 10. Non-limiting examples ofsuitable high thermal conductivity materials for the first body of highthermal conductivity material 14 include one or more of elementalgallium, gallium alloys, paraffin with between eighteen and thirtycarbons, sodium sulfate, lauric acid, trimethylolethane, p-lattic acid,methyl palmitate, camphenilone, caprylone, heptadecanone,1-cyclohexyloctadecane, 4-heptadecanone, 3-heptadecanone,2-heptadecanone, 9-heptadecanone, camphene, thymol, p-dichlorobenzene,heptaudecanoic acid, beeswax, glyolic acid, glycolic acid, capric acid,eladic acid, and pentadecanoic acid.

In use, heat generated by the heat source HS is transferred byconduction, into the first body of high thermal conductivity material14. In the embodiments where the high thermal conductivity material is asolid phase change material, this may result in melting of at least aportion of the first body of high thermal conductivity material 14,which absorbs some of the heat from the heat source and forms aconductive melted high thermal conductivity material layer 16 within thefirst body of high thermal conductivity material 14 and disposed indirect contact with the heat source HS (as shown in FIG. 1B). Therefore,the conductive melted high thermal conductivity material layer 16 istypically an at least partially liquid form of the first body of highthermal conductivity material 14. In embodiments where the high thermalconductivity material is a liquid, the first body of high thermalconductivity material 14 is immediately adjacent to the heat source HS(as shown in FIG. 1A).

The heat stored in the first body of high thermal conductivity material14 and the heat stored in the conductive melted high thermalconductivity material layer 16, if present, may then be transferred byconduction and convection, respectively, to the thermally conductivehousing 12. Heat transferred to the thermally conductive housing 12 maythen be transferred by convection into the external environment, and byconvection through the fins 22, if present, thereby cooling the heatsink 10. The vibrating base 20 may propagate oscillating waves throughthe thermally conductive housing 12, the first body of high thermalconductivity material 14, and/or the thermally conductive melted highthermal conductivity material layer 16, if present, to reach the directcontact interface 28, generating active dynamic molecular motion anddilating the direct contact interface 28, and thereby increasing therate of heat transfer from the heat source HS to the first body of highthermal conductivity material 14 and the conductive melted high thermalconductivity material layer 16, if present. Thus the heat from the heatsource HS is quickly and efficiently transferred to the ambientenvironment.

In the alternative embodiment of FIGS. 2A and 2B, the heat sink withvibration enhanced heat transfer, designated generally as 100, is also aheat sink formed from a first body of high thermal conductivity material114 disposed within a thermally conductive housing 112 such that atleast one contact face 130 of the first body of high thermalconductivity material 114 is exposed, forming a direct contact interface128 with at least one face of at least one heat source HS that requirescooling. The thermally conductive housing 112 again has at least onewall 132 and at least one contact face 134, and said contact face 134 ofsaid thermally conductive housing 112 is adapted to be in direct contactwith a vibrating base 120. In this alternative embodiment, the heatsource HS is an immiscible liquid 118. As in the previous embodiment, itshould be further understood that the overall configuration and relativedimensions of the thermally conductive housing 112, the first body ofhigh thermal conductivity material 114, and the vibrating base 120 areshown for purposes of illustration only.

The thermally conductive housing 112 may be selected from any suitablematerial that is compatible with the selected first body of high thermalconductivity material 114. For example, aluminum would not be used as athermally conductive housing 112 material when the first body of highthermal conductivity material 114 includes elemental gallium. The atleast one wall 132 of the thermally conductive housing 112 may have aplurality of fins 122 mounted to at least a portion thereof, eitheroutside or inside of the first body of high thermal conductivitymaterial 114. It should be understood that the positioning, overallconfiguration, relative dimensions, and number of thermally conductivefins 122 are shown for exemplary purposes only.

The first body of high thermal conductivity material 114 may be formedfrom at least one high thermal conductivity material. The at least onehigh thermal conductivity material may be liquid at intended operatingconditions, or it may be a solid phase change material. The at least onehigh thermal conductivity material is selected such that it has a highthermal conductivity and, if the high thermal conductivity materialselected is a solid phase change material, is selected such that it hasa melting point between the temperature of the external environmentwithin which the heat sink 100 is intended to operate and the maximumoperating temperature of the heat source HS. As a non-limiting example,if a heat sink 100 is intended to operate in a room maintained at 20° C.and to cool a heat source with a maximum operating temperature of 60°C., elemental gallium having a melting point of approximately 30° C.might be selected for the first body of high thermal conductivitymaterial 114. If the at least one high thermal conductivity material isa liquid under the intended operating conditions and the heat source isa liquid, the selected material may have a higher density than thedensity of the heat source material. In the alternative embodiment ofFIGS. 2A and 2B, the at least one high thermal conductivity materialforming the first body of high thermal conductivity material 114 is alsoselected such that the immiscible liquid 118 will be immiscible with anyliquid or melted portion of the first body of high thermal conductivitymaterial 114 that may form during use of the heat sink 100. Non-limitingexamples of suitable high thermal conductivity materials for the firstbody of high thermal conductivity material 114 include one or more ofelemental gallium, gallium alloys, paraffin with between eighteen andthirty carbons, sodium sulfate, lauric acid, trimethylolethane, p-latticacid, methyl palmitate, camphenilone, caprylone, heptadecanone,1-cyclohexyloctadecane, 4-heptadecanone, 3-heptadecanone,2-heptadecanone, 9-heptadecanone, camphene, thymol, p-dichlorobenzene,heptaudecanoic acid, beeswax, glyolic acid, glycolic acid, capric acid,eladic acid, and pentadecanoic acid.

In use, heat generated by the heat source HS is transferred, viaconduction, into the first body of high thermal conductivity material114. In embodiments where the high thermal conductivity material is asolid phase change material, this may result in melting of at least aportion of the first body of high thermal conductivity material 114,which absorbs some of the heat from the heat source HS and forms aconductive melted high thermal conductivity material layer 116 withinthe first body of high thermal conductivity material 114 and disposed indirect contact with the heat source HS (as shown in FIG. 2B). Therefore,the conductive melted high thermal conductivity material layer 116 istypically an at least partially liquid form of the first body of highthermal conductivity material 114. In embodiments where the high thermalconductivity material is a liquid, the first body of high thermalconductivity material 114 is immediately adjacent to the heat source HS(as shown in FIG. 2A).

The heat stored in the first body of high thermal conductivity material114 and the heat stored in the conductive melted high thermalconductivity material layer 116, if present, may then be transferred byconduction and convection, respectively, to the thermally conductivehousing 112. Heat transferred to the thermally conductive housing 112may then be transferred by convection into the external environment, andby convection through the fins 122, if present, thereby cooling the heatsink 100. The vibrating base 120 may propagate oscillating waves throughthe thermally conductive housing 112, the first body of high thermalconductivity material 114, and/or the thermally conductive melted highthermal conductivity material layer 116, if present, to reach the directcontact interface 128, generating active dynamic molecular motion anddilating the direct contact interface 128, and thereby increasing therate of heat transfer from the heat source HS to the first body of highthermal conductivity material 114 and the conductive melted high thermalconductivity material layer 116, if present. Thus the heat from the heatsource HS is quickly and efficiently transferred to the ambientenvironment.

In the alternative embodiment of FIGS. 2A and 2B, a plurality of tubes124 is provided. In the example of FIGS. 2A and 2B, two such tubes 124are shown, each having a first end 136 and an opposed second end 138;however, it should be understood that any number of tubes 124 may beused. Each of the plurality of tubes 124 is positioned in and traversesthe first body of high thermal conductivity material 114 and thethermally conductive housing 112, such that the first end 136 and thesecond end 138 of each of the plurality of tubes 124 is positionedoutside of the first body of high thermal conductivity material 114 andthe thermally conductive housing 112. As shown in FIG. 2B, one or moreof the plurality of tubes 124 may also traverse at least a portion ofthe conductive melted high thermal conductivity material layer 116and/or at least a portion of the immiscible liquid HS. In an embodiment,the first end 136 and the second end 138 of one or more of the pluralityof tubes 124 are closed. In an alternative embodiment, the first end 136and the second end 138 of one or more of the plurality of tubes 124 arein open fluid communication with the external environment. In thealternative embodiment of FIGS. 2A and 2B, each of the plurality oftubes 124 may have a plurality of thermally conductive fines 126 mountedon at least a portion thereof inside and/or outside the first body ofhigh thermal conductivity material 114, the conductive melted highthermal conductivity material layer 116, the immiscible liquid HS, andthe thermally conductive housing 112. The plurality of tubes 124 mayfurther improve the rate at which the heat sink 100 transfers heat fromthe heat source HS to the external environment by providing a largesurface area for conduction of heat from the first body of high thermalconductivity material 114 and/or the conductive melted high thermalconductivity material layer 116.

In the alternative embodiment of FIGS. 3A and 3B, the heat sink withvibration enhanced heat transfer, designated generally as 200, is a heatsink formed from a first body of high thermal conductivity material 214disposed within a thermally conductive housing 212 such that at leastone contact face 230 of the first body of high thermal conductivitymaterial 214 is exposed, forming a direct contact interface 228 with atleast one face of at least one heat source HS that requires cooling. Thethermally conductive housing 212 has at least one wall 232 and at leastone contact face 234, and said contact face 234 of said thermallyconductive housing 212 is adapted to be in direct contact with avibrating base 220. In this alternative embodiment, the heat source HSis an immiscible liquid 218. It should be further understood that theoverall configuration and relative dimensions of the thermallyconductive housing 212, the first body of high thermal conductivitymaterial 214, and the vibrating base 220 are shown for purposes ofillustration only.

In the alternative embodiment of FIGS. 3A and 3B, at least one innerchamber 244 is disposed within the first body of high thermalconductivity material 214. The at least one inner chamber 244 may beregularly shaped as shown in FIG. 3A, or irregularly shaped as shown inFIG. 3B. The at least one inner chamber 244 is adapted to receive asecond body of high thermal conductivity material 215. In an embodiment,the at least one inner chamber 244 may be formed directly as a space inthe first body of high thermal conductivity material 214. In thisembodiment, the at least one inner chamber 244 is filled with the secondbody of high thermal conductivity material 215 and is in direct contactwith and completely enclosed within, but separate from, the first bodyof high thermal conductivity material 214. In another embodiment, the atleast one inner chamber 244 may be formed from a high thermalconductivity material, such as the material selected to form thethermally conductive housing 212. In this embodiment the high thermalconductivity material forms the walls of the at least one inner chamber244, such that the second body of high thermal conductivity material 215is in direct contact with and completely enclosed within the wallsformed from the high thermal conductivity material. That is to say, indifferent embodiments the second body of high thermal conductivitymaterial 215 may be encapsulated by the at least one inner chamber 244,or the second body of high thermal conductivity material 215 may beun-encapsulated by the at least one inner chamber 244, but still locatedand fully contained within, while being separate from, the first body ofhigh thermal conductivity material 214.

The thermally conductive housing 212 may be selected from any suitablematerial that is compatible with the selected first body of high thermalconductivity material 214. For example, aluminum would not be used as athermally conductive housing 212 material when the first body of highthermal conductivity material 214 includes elemental gallium. The atleast one wall 232 of the thermally conductive housing 212 may have aplurality of fins 222 mounted to at least a portion thereof, eitheroutside or inside of the first body of high thermal conductivitymaterial 214. It should be understood that the positioning, overallconfiguration, relative dimensions, and number of thermally conductivefins 222 are shown for exemplary purposes only.

The first body of high thermal conductivity material 214 may be formedfrom at least one high thermal conductivity material. The at least onehigh thermal conductivity material may be liquid at intended operatingconditions, or it may be a solid phase change material. The at least onehigh thermal conductivity material is selected such that it has a highthermal conductivity and, if the high thermal conductivity materialselected is a solid phase change material, is selected such that it hasa melting point between the temperature of the external environmentwithin which the heat sink 200 is intended to operate and the maximumoperating temperature of the heat source HS. As a non-limiting example,if the heat sink 200 is intended to operate in a room maintained at 20°C. and to cool a heat source with a maximum operating temperature of 60°C., elemental gallium having a melting point of approximately 30° C.might be selected for the first body of high thermal conductivitymaterial 214. If the at least one high thermal conductivity material isa liquid under the intended operating conditions and the heat source isa liquid, the selected material may have a higher density than thedensity of the heat source material. In the alternative embodiment ofFIGS. 3A and 3B, the at least one high thermal conductivity materialforming the first body of high thermal conductivity material 214 is alsoselected such that the immiscible liquid 218 will be immiscible with anymelted portion of the first body of high thermal conductivity material214 that may form during use of the heat sink 200. Non-limiting examplesof suitable high thermal conductivity materials for the first body ofhigh thermal conductivity material 214 include one or more of elementalgallium, gallium alloys, paraffin with between eighteen and thirtycarbons, sodium sulfate, lauric acid, trimethylolethane, p-lattic acid,methyl palmitate, camphenilone, caprylone, heptadecanone,1-cyclohexyloctadecane, 4-heptadecanone, 3-heptadecanone,2-heptadecanone, 9-heptadecanone, camphene, thymol, p-dichlorobenzene,heptaudecanoic acid, beeswax, glyolic acid, glycolic acid, capric acid,eladic acid, and pentadecanoic acid.

The second body of high thermal conductivity material 215 is formed fromat least one solid phase change material, the at least one solid phasechange material being selected such that it has a higher specific heatcapacity than the specific heat capacity of the high thermalconductivity material selected for the first body of high thermalconductivity material 214 and a lower phase change temperature than thephase change temperature of the at high thermal conductivity materialselected for the first body of high thermal conductivity material 214.Non-limiting examples of suitable solid phase change materials for thesecond body of high thermal conductivity material 215 include one ormore of elemental gallium, gallium alloys, paraffin with betweeneighteen and thirty carbons, sodium sulfate, lauric acid,trimethylolethane, p-lattic acid, methyl palmitate, camphenilone,caprylone, heptadecanone, 1-cyclohexyloctadecane, 4-heptadecanone,3-heptadecanone, 2-heptadecanone, 9-heptadecanone, camphene, thymol,p-dichlorobenzene, heptaudecanoic acid, beeswax, glyolic acid, glycolicacid, capric acid, eladic acid, and pentadecanoic acid.

In use, heat generated by the heat source HS is transferred byconduction, into the first body of high thermal conductivity material214. In the embodiments where the high thermal conductivity material isa solid phase change material, this may result in melting of at least aportion of the first body of high thermal conductivity material 214,which absorbs some of the heat from the heat source and forms aconductive melted high thermal conductivity material layer 216 withinthe first body of high thermal conductivity material 214 and disposed indirect contact with the heat source HS (as shown in FIGS. 3A and 3B).Therefore, the conductive melted high thermal conductivity materiallayer 216 is typically an at least partially liquid form of the firstbody of high thermal conductivity material 214. In embodiments where thehigh thermal conductivity material is a liquid, the first body of highthermal conductivity material 214 is immediately adjacent to the heatsource HS and the second body of high thermal conductivity material 215is un-encapsulated by the at least one inner chamber 244.

The heat stored in the first body of high thermal conductivity material214 and the heat stored in the conductive melted high thermalconductivity material layer 216, if present, may then be transferred byconduction and convection, respectively, to the thermally conductivehousing 212. Heat transferred to the thermally conductive housing 212may then be transferred by convection into the external environment, andby convection through the fins 222, if present, thereby cooling the heatsink 200. The vibrating base 220 may propagate oscillating waves throughthe thermally conductive housing 212, the first body of solid highthermal conductivity material 214, the second body of high thermalconductivity material 215, and/or the thermally conductive melted highthermal conductivity material layer 216, if present, to reach the directcontact interface 228, generating active dynamic molecular motion anddilating the direct contact interface 228, and thereby increasing therate of heat transfer from the heat source HS to the first body of highthermal conductivity material 214 and the conductive melted high thermalconductivity material layer 216, if present. Thus the heat from the heatsource HS is quickly and efficiently transferred to the ambientenvironment.

In the alternative embodiment of FIGS. 4A and 4B, the heat sink withvibration enhanced heat transfer, designated generally as 300, is againa heat sink formed from a first body of high thermal conductivitymaterial 314 disposed within a thermally conductive housing 312 suchthat at least one contact face 330 of the first body of high thermalconductivity material 314 is exposed, forming a direct contact interface328 with at least one face of at least one heat source HS that requirescooling. Similar to previous embodiments, the thermally conductivehousing 312 has at least one wall 332 and at least one contact face 334,and said contact face 334 of said thermally conductive housing 312 isadapted to be in direct contact with a vibrating base 320. In thisalternative embodiment, the heat source HS is an immiscible liquid 318.Similar to the previous embodiments, it should be further understoodthat the overall configuration and relative dimensions of the thermallyconductive housing 312, the first body of high thermal conductivitymaterial 314, and the vibrating base 320 are shown for purposes ofillustration only.

As in previous embodiments, the thermally conductive housing 312 may beselected from any suitable material that is compatible with the selectedfirst body of high thermal conductivity material 314. For example,aluminum would not be used as a thermally conductive housing 312material when the first body of high thermal conductivity material 314includes elemental gallium.

In the alternative embodiment of FIGS. 4A and 4B, at least one thermallyconductive vertical stud 346, having a first end 340 and a second end342, is positioned within the first body of high thermal conductivitymaterial 314. The first end 340 of the at least one thermally conductivevertical stud 346 is coterminous with the at least one contact face 334of the thermally conductive housing 312. Thus, the first end 340 of theat least one thermally conductive vertical stud 346 is also in directcontact with the vibrating base, 320. The second end 342 of the at leastone thermally conductive vertical stud 346 is positioned within theimmiscible liquid 318. The at least one thermally conductive verticalstud 346 may be made of rigid material or of a non-rigid material. Theat least one thermally conductive vertical stud 346 may be composed ofany thermally conductive material. In a further embodiment, the at leastone thermally conductive vertical stud 346 may be composed of a materialthat is not a good thermal conductor. The surface of the at least onethermally conductive vertical stud 346 may be made from a malleableconducting material. Fins 326 may be attached to the surface of one ormore of the thermally conductive vertical studs 346. The fins 326 may berigid or flexible. Further, the surface of the one or more thermallyconductive vertical studs 346 may bear irregularities such as grooves,bends, or other shapes to intensify heat transfer.

The first body of high thermal conductivity material 314 may be formedfrom at least one high thermal conductivity material. The at least onehigh thermal conductivity material may be liquid at intended operatingconditions, or it may be a solid phase change material. The at least onehigh thermal conductivity material is selected such that it has a highthermal conductivity and, if the high thermal conductivity materialselected is a solid phase change material, is selected such that it hasa melting point between the temperature of the external environmentwithin which the heat sink 300 is intended to operate and the maximumoperating temperature of the heat source HS. As a non-limiting example,if a heat sink 300 is intended to operate in a room maintained at 20° C.and to cool a heat source with a maximum operating temperature of 60°C., elemental gallium having a melting point of approximately 30° C.might be selected for the first body of high thermal conductivitymaterial 314. If the at least one high thermal conductivity material isa liquid under the intended operating conditions and the heat source isa liquid, the selected material may have a higher density than thedensity of the heat source material. In the alternative embodiment ofFIG. 4 , the at least one high thermal conductivity material forming thefirst body of high thermal conductivity material 314 is also selectedsuch that the immiscible liquid 318 will be immiscible with any meltedportion of the first body of high thermal conductivity material 314 thatmay form during use of the heat sink 300. Non-limiting examples ofsuitable high thermal conductivity materials for the first body of highthermal conductivity material 314 include one or more of elementalgallium, gallium alloys, paraffin with between eighteen and thirtycarbons, sodium sulfate, lauric acid, trimethylolethane, p-lattic acid,methyl palmitate, camphenilone, caprylone, heptadecanone,1-cyclohexyloctadecane, 4-heptadecanone, 3-heptadecanone,2-heptadecanone, 9-heptadecanone, camphene, thymol, p-dichlorobenzene,heptaudecanoic acid, beeswax, glyolic acid, glycolic acid, capric acid,eladic acid, and pentadecanoic acid.

As in previous embodiments, in use, heat generated by the heat source HSis transferred by conduction, into the first body of high thermalconductivity material 314. In the embodiments where the high thermalconductivity material is a solid phase change material, this may resultin melting of at least a portion of the first body of high thermalconductivity material 314, which absorbs some of the heat from the heatsource and forms a conductive melted high thermal conductivity materiallayer 316 within the first body of high thermal conductivity material314 and disposed in direct contact with the heat source HS. Therefore,the conductive melted high thermal conductivity material layer 316 istypically an at least partially liquid form of the first body of highthermal conductivity material 314 (as shown in FIG. 4 ). In embodimentswhere the high thermal conductivity material is a liquid, the highthermal conductivity material 314 is immediately adjacent to the heatsource (not shown).

The heat stored in the first body of high thermal conductivity material314 and the heat stored in the conductive melted high thermalconductivity material layer 316, if present, may then be transferred byconduction and convection, respectively, to the thermally conductivehousing 312. Heat transferred to the thermally conductive housing 312may then be transferred by convection into the external environment, andby convection through the fins 322, if present, thereby cooling the heatsink 300. The vibrating base 320 may propagate oscillating waves throughthe thermally conductive housing 312, the first body of high thermalconductivity material 314, the at least one thermally conductivevertical stud 346, and/or the thermally conductive melted high thermalconductivity material layer 316, if present, to reach the direct contactinterface 328, generating active dynamic molecular motion and dilatingthe direct contact interface 328, and thereby increasing the rate ofheat transfer from the heat source HS to the first body of high thermalconductivity material 314 and the conductive melted high thermalconductivity material layer 316, if present.

In the alternative embodiment of FIGS. 4A and 4B, the at least onethermally conductive vertical stud 346 may by constructed of a rigidmaterial, and thus the at least one thermally conductive vertical stud346 may also vibrate, leading to further disturbance of the directcontact interface 328 and further enhancing the rate of heat transferfrom the heat source HS to the first body of high thermal conductivitymaterial 314 and the conductive melted high thermal conductivitymaterial layer 316, if present. In the alternative embodiment of FIGS.4A and 4B, the at least one thermally conductive vertical stud 346 maybe made of a non-rigid material, and thus the at least one thermallyconductive vertical stud 346 may move at a different rate in response tovibration than the thermally conductive housing 312. In the alternativeembodiment of FIG. 4A, the at least one thermally conductive verticalstud 346 may be constructed of a high thermal conductivity material, ora low thermal conductivity material, or a non-conducting material. Ifmore than one thermally conductive vertical stud 346 is present, eachmay be made of the same or different material. If the at least onethermally conductive vertical stud 346 is constructed of a high thermalconductivity material, this stud may assist in conducting heat from thesurrounding first body of high thermal conductivity material 314directly to the vibrating base 320. If the at least one thermallyconductive vertical stud 346 is constructed of a low-conducting or anon-conducting material, the at least one thermally conductive verticalstud 346 will agitate the surrounding first body of high thermalconductivity material 314 in response to vibration, assisting with heattransfer. Thus the heat from the heat source HS is quickly andefficiently transferred to the ambient environment.

In the alternative embodiment of FIG. 4B, at least one internal chamber350 is disposed within the at least one thermally conductive verticalstud 346. It should be further understood that the overall configurationand relative dimensions of the at least one inner chamber 350 are shownfor illustration purposes only, and the at least one internal chamber350 may be regularly shaped or irregularly shaped. The at least oneinternal chamber 350 is adapted to receive a body of phase changematerial. In an embodiment, the at least one internal chamber 350 may beformed directly as a space completely enclosed within the at least onethermally conductive vertical stud 346. The body of phase changematerial may comprise one or more phase change materials selected forchanging phase at a lower temperature than the anticipated operatingtemperature of the heat source HS, or the phase change temperature ofthe first body of high thermal conductivity material 314, if the firstbody of high thermal conductivity material 314 is intended to operate asa phase change material. In the alternative embodiment of FIG. 4B, theat least one thermally conductive vertical stud 346 may comprise a highconductivity material, to aid in heat transfer from the heat source tothe phase change material disposed within the at least one internalchamber 350. Non-limiting examples of suitable phase change materialsinclude one or more of elemental gallium, gallium alloys, paraffin withbetween eighteen and thirty carbons, sodium sulfate, lauric acid,trimethylolethane, p-lattic acid, methyl palmitate, camphenilone,caprylone, heptadecanone, 1-cyclohexyloctadecane, 4-heptadecanone,3-heptadecanone, 2-heptadecanone, 9-heptadecanone, camphene, thymol,p-dichlorobenzene, heptaudecanoic acid, beeswax, glyolic acid, glycolicacid, capric acid, eladic acid, and pentadecanoic acid.

In the alternative embodiment of FIG. 4B, heat transferred to the atleast one thermally conductive vertical stud 346 may be transferred tothe body of phase change material within the at least one internalchamber 350. Thus, the body of phase change material may change phase,providing an internal reservoir for heat storage and allowing the heatsink to more efficiently cool the heat source HS.

The following examples illustrate the present teachings.

Example 1 Vibration Experiments

Experiments were conducted to determine the optimal conditions foroperation of a vibration enhanced heat sink. In these experiments, solidgallium was placed within a mild steel cylindrical cup and a layer ofhot water (a heat source) was poured above the gallium. K-type omegathermacouples recorded temperature fluctuations from the heat source. Acontrol test without vibration was established as a baseline, and isreferred to herein as testing group A1. A B&K LDS shaker was used toprovide vibrations. Vertical sinusoidal vibrations were applied to theheat sink at three levels of frequency (20, 35, and 50 Hz) and at threeamplitudes (0.3, 0.5, and 0.7 mm). The amplitude values tested representpeak to peak displacement. Each test was repeated three times.

For each test group, the test was started at an initial temperature of15° C. and hot water heated to 70° C. was poured over the solid gallium.The solid gallium's temperature measurement rapidly rose to the meltingpoint of 30° C. Test groups at higher amplitudes or frequencies reachedthe melting point of the gallium faster than ones conducted at lowervalues of these parameters. This supports the conclusion that heattransfer rates from the heat source into the gallium were increased byapplication of the vibrations to the gallium.

As illustrated in FIGS. 5-7 , the application of vibrations to the heatsink significantly increased the rate of cooling of the hot water (heatsource) in a time and amplitude dependent manner. These results wereused to calculate the Time Savings, or the percentage of time that ittook for a particular test case to cool to a given temperature rangewhen compared to testing group A1. These results suggest that whenexposed to vibration this heat sink displays improved transfer of heatfrom the liquid interface region to the solid gallium and between theliquid interface region and the heat source. These results are presentedin Table 1 below.

TABLE 1 Time Savings % 70-60° C. 60-50° C. 50-40° C. 40-32° C. 20 Hz,0.30 mm 7.41 4.76 5.62 17.61 20 Hz, 0.50 mm 22.22 33.33 48.31 67.44 20Hz, 0.70 mm 48.15 59.52 68.54 75.75 35 Hz, 0.30 mm 14.81 11.9 17.9831.23 35 Hz, 0.50 mm 40.74 38.1 49.44 68.11 35 Hz, 0.70 mm 59.26 66.6776.4 83.06 50 Hz, 0.30 mm 29.63 26.19 39.33 40.2 50 Hz. 0.50 mm 59.2666.67 75.28 82.06 50 Hz, 0.70 mm 74.07 78.57 83.15 89.7

Cooling Efficiency was also calculated by dividing the water temperaturedrop at a particular moment by the theoretical maximum temperature drop(based upon an ambient temperature of 23° C. and a starting heat sourcetemperature of 70° C.). While the maximum cooling efficiency for allcases is approximately 84%, when vibrations are applied the time that ittakes to reach this maximum cooling efficiency is reduced. Notably, thiseffect also varies significantly with amplitude.

Features of each of the disclosed embodiments may be used in other ofthe disclosed embodiments. For example, the tube of the embodiment ofFIG. 2A can be used in the embodiment of FIG. 3A, and so on.

It is to be understood that the heat sinks with vibration enhanced heattransfer is not limited to the specific embodiments described above, butencompasses any and all embodiments within the scope of the genericlanguage of the following claims enabled by the embodiments describedherein, or otherwise shown in the drawings or described above in termssufficient to enable one of ordinary skill in the art to make and usethe claimed subject matter.

We claim:
 1. A heat sink with vibration enhanced heat transfer adaptedfor cooling of a liquid heat source, comprising: a thermally conductivehousing having at least one contact face and at least one wall; a firstbody made of thermal conductive phase change material disposed withinthe thermally conductive housing, the first body of thermal conductivematerial having a first contact face disposed for direct contact with aheat source to be cooled at one end of the housing and a second contactface located at a first contact face of the housing; and a vibratingbase, the vibrating base disposed in direct contact with an entiresecond contact face of the thermally conductive housing; wherein thevibrating base is configured to propagate oscillating waves through thethermally conductive housing and the second contact face of the firstbody of thermal conductive material to reach the first contact facedisposed for direct contact with the heat source; and wherein the firstbody of thermal conductive phase change is capable of forming an atleast partially liquid conductive melted thermal conductive materiallayer in direct contact with the liquid heat source.
 2. The heat sink asrecited in claim 1, further comprising a plurality of thermallyconductive fins mounted on at least a portion of the at least one wallof the thermally conductive housing.
 3. The heat sink as recited inclaim 2, wherein the plurality of fins are constructed of a materialselected from the group consisting of a first material having a firststiffness, a second material having a second stiffness less than thefirst stiffness, and a combination of materials having first and secondstiffnesses.
 4. The heat sink as recited in claim 1, further comprisingat least one tube having opposed first and second ends, wherein the tubeis positioned in and traverses the thermally conductive housing and oneor more materials therein such that the opposed first and second ends ofthe at least one tube are positioned outside of the thermally conductivehousing.
 5. The heat sink as recited in claim 4, further comprising aplurality of thermally conductive fins mounted on at least a portion ofthe at least one tube.
 6. The heat sink as recited in claim 5, whereinthe plurality of fins are constructed of a material selected from thegroup consisting of a first material having a first stiffness, a secondmaterial having a second stiffness less than the first stiffness, and acombination of materials having first and second stiffnesses.
 7. Theheat sink as recited in claim 1, wherein the first body of thermalconductive material is a solid phase change material.
 8. The heat sinkas recited in claim 1, wherein the first body of thermal conductivematerial is a liquid.
 9. The heat sink as recited in claim 8, whereinthe liquid first body of thermal conductivity material has a firstpredetermined density and the liquid heat source has a secondpredetermined density lower than the first predetermined density. 10.The heat sink as recited in claim 1, further comprising a second heatsource within the housing and in direct contact with the first body ofthermal conductive material, wherein the second heat source is athermally conductive material.
 11. The heat sink as recited in claim 1,further comprising at least one second body made of thermal conductivematerial disposed within the first body of thermal conductive material,wherein the at least one second body comprises a different thermalconductive material from the first body of thermal conductive material.12. The heat sink as recited in claim 11, wherein the second body ofthermal conductive phase change material has a first specific heatcapacity and the first body of thermal conductive phase change materialhas a second specific heat capacity lower than the first specific heatcapacity.
 13. The heat sink as recited in claim 1, further comprising atleast one second body made of thermal conductive material disposedwithin the first body of thermal conductive material, wherein the atleast one second body comprises a distinct entity from the first body ofthermal conductive material.
 14. The heat sink as recited in claim 1,wherein the vibrating base has a level of frequency between 20 Hz and 50Hz and an amplitude within the range of 0.3 mm and 0.7 mm.